This invention pertains to co-processing coal/oil feedstocks in a two-stage catalytic hydroconversion process. It pertains particularly to such coal/oil co-processing to produce higher percentage hydroconversion and increased yields of low-boiling hydrocarbon distillate liquid products, while yields of hydrocarbon gases and heavy resid materials.
Coal/oil co-processing using a single stage catalytic ebullated bed reactor, has been shown to be an effective technique for simultaneous conversion of coal and residual oils to produce predominantly hydrocarbon liquid products, as disclosed by U.S. Pat. No. 4,054,405 to Chervenak, et al. At high percentage conversion levels, the single stage hydrogenation process produces undesirably high yields of byproduct hydrocarbon gas (C.sub.1 -C.sub.3) and product quality decreases, i.e., the N.sub.2 and sulfur contents of the distillate liquid products increase. Several other processes for simultaneous processing of coal and petroleum feeds using two reaction stages have been proposed, such as disclosed by U.S. Pat. Nos. 3,870,621 to Arnold; 4,306,960 to Gleim, and 4,330,390 to Rosenthal, et al. However, these processes all have shortcomings and do not achieve the flexibility and high yields of low-boiling hydrocarbon distillate liquids desired. Significantly improved results have now been achieved by the present two-stage catalytic coal/oil co-processing process for blended coal and oil feedstocks.